Purpose. The study is purposed at analyzing frequency, speed and duration of the alongshore winds inducing the Ekman upwelling near the Southern Coast of Crimea.Methods and Results. The 6-hour data on the wind speed components at the 10 m height derived from the ERA5 atmospheric reanalysis for 1979-2021, as well as the data of temperature monitoring performed at the Black Sea hydrophysical sub-satellite polygon of Marine Hydrophysical Institute, Russian Academy of Sciences, are used. Frequency and speed of the winds (namely, the southwestern, western and northwestern ones) favorable for development of upwelling near the Southern Coast of Crimea are considered. The multi-year data based calculations show that the seasonal variability in frequency of each of these winds is of an individual character, whereas their average speeds change the same decreasing from winter to summer. In summer, frequency of the western and northwestern winds increases, and that of the southwestern ones - decreases. The total frequency of favorable winds is the highest in June (maximum values), July, January and December. The lowest frequency values occur in August and October. The interannual changes in speed and frequency of the westerly directions winds result in changes in the upwelling numbers and durations. A significant positive relationship was obtained between the mean speed and frequency of these winds in June and the number of upwellings recorded by a water temperature decrease. The correlation coefficients were 0.74 and 0.68, respectively.Conclusions. The wind conditions for arising of upwelling near the Southern Coast of Crimea are observed in all the months of a year, but the most favorable ones - in June, July, December and January due to the high frequency of westerly winds. High wind speed is also a significant factor for the development of upwelling.

Purpose. The purpose consists in joint analysis of satellite observations of the internal waves surface manifestations near the Crimean coast, and the results of numerical simulation of influence of seasonal thermohaline conditions and the Black Sea shelf relief on their structure, dynamics and intensification. Methods and Results. Based on the analysis of remote sensing data using high-resolution sensors of the Landsat -8, Sentinel -2 satellites and the theoretical estimates, the main spatial and temporal characteristics of the internal waves on the Black Sea shelf near the Herakles Peninsula were determined. Due to the temperature and salinity data obtained from the vessel measurements in 1951–2008 from the Oceanographic Data Bank of Marine Hydrophysical Institute and the satellite measurements, the structure of the density stratification of water was investigated, and the buoyancy frequency profiles in the shelf and slope area from Yevpatoria to Yalta were obtained. The vertical velocity profiles of internal waves of the first three modes on the shelf were constructed. It was revealed that phase velo city of the internal waves of the first mode in the deep-sea part on the studied sections varied within the range 2.6–5 m/s, the waves of the second mode – within 1.1–2.3 m/s, and the waves of the third mode – within 0.7–1.4 m/s. The average length of the waves detected from the satellite data was 0.4 km; the longest waves, about 1.1 km, observed most often between Yevpatoria and Sevastopol, propagated predominantly to the northeast. Within the same train, wave dispersion also occurred resulting in the wavelength diminution to 0.1–0.3 km. Conclusions. The stated assumption on the cause of generation of intense internal waves conditioned by interaction of the Rim Current jet with the shelf edge was confirmed by the results of numerical calculations. Spatial and temporal characteristics of the internal waves, the integrated data of remote sensing and the simulation results make it possible to estimate vertical exchange at the shelf and to determine the depth of the maximal Vaisal – Brent frequency.

The paper considers the internal waves on the shelf of the Crimean coast, their structure and dynamics at the periphery of the Black Sea basin. Manifestations of internal waves were studied by numerical experiments and by processing of remote sensing data from high-resolution data. Maps of the vertical velocity of the first three modes of internal waves on the shelf of the Crimean coast were constructed. The phase velocity of the internal waves in the deep part of the sea for the first mode at the given profiles varies from 2.6 to 5 ms(-1); for the waves of the second mode-1.1-2.3 ms(-1); for the waves of the third mode-0.7-1.4 ms(-1). Wavelengths detected from the satellite data had a mean value of 0.4 km. The longest waves, around 0.8 km, were observed between Sevastopol and Yevpatoria. During June, 2017 the waves of 2nd and 3rd modes were observed in the area of study the most frequently.

Purpose. The purpose consists in a combined analysis of satellite observations of surface manifestations of internal waves near the Crimean coast and the results of numerical simulation of influence of seasonal thermohaline conditions and the relief on their structure, dynamics and intensification. Methods and Results. Based on the analysis of remote sensing data using high-resolution sensors of the Landsat-8 and Sentinel-2 satellites and the theoretical estimates, the main spatial and temporal characteristics of the internal waves on the Black Sea shelf near the Heracles Peninsula were determined. According to the temperature and salinity data obtained from the satellite measurements and the research vessels measurements in 1951–2008 from the Oceanographic Data Bank of Marine Hydrophysical Institute, the structure of density stratification was investigated, and buoyancy frequency profiles in the shelf and slope area from Yevpatoria to Yalta were obtained. Vertical velocity profiles of internal waves of the first three modes on the shelf were constructed. It was revealed that phase velocity of the internal waves of the first mode in the deep-sea part varied within the range of 2.6–5 m/s, the waves of the second mode – within 1.1–2.3 m/s, and the waves of the third mode – within 0.7–1.4 m/s. The average length of the waves detected from the satellite data was 0.4 km; the longest waves, about 1.1 km, were observed most often between Yevpatoria and Sevastopol, propagating predominantly to the northeast. Within the same train, wave dispersion occurred resulting in the wavelength diminution to 0.1–0.3 km. Conclusions. The stated assumption on the cause of generation of intense internal waves conditioned by the interaction of the Rim Current jet with the shelf edge was confirmed by the results of numerical calculations. Spatial and temporal characteristics of the internal waves, the integrated data of remote sensing and the modeling results make it possible to estimate vertical exchange at the shelf and to determine the depth of the maximum Brunt–Väisälä frequency.

This work investigates the regional specifics of the appearance and propagation of internal waves at the shelf of the Black Sea. The parameters of horizontal inhomogeneity associated with changes in the bottom relief and density of seawater that lead to instability and destruction of internal waves are studied. The numerical experiments for the spring and summer seasons on transects normal to the coast are conducted using data of temperature and salinity from the Bank of oceanographic data of the Marine Hydrophysical Institute of RAS. The article touches upon the actual theme of adaptation of satellite images obtained from open sources when solving oceanographic problems. The result of the processing of remote sensing data was information about the speeds and wavelengths for the observed phenomena. These values are used to recover the depth of the seasonal pycnocline within a two-layer approximation of the vertical density structure. For different bottom slopes and seasonal profiles of the buoyancy frequency, sites are determined where the transition from supercritical to critical or subcritical conditions is possible in the region of the Crimean coast.

В рамках исследования структуры циркуляции Черного моря на глубинах ниже главного пикноклина представлены данные о преобладающих направлениях, изменчивости и скорости течений. Данные о вертикальных профилях течений были получены контактными методами в ходе экспедиционных работ Морского гидрофизического института. Для исследования глубинных течений были выбраны 25 станций, которые содержали измерения на горизонте 500 м и более. Приводятся характеристики приборов и географическое расположение станций. Периоды зондирований на станциях варьировали в пределах от нескольких часов до двух месяцев. Обеспеченность данными как по времени, так и по пространству существенно неравномерна, однако в работе впервые описан и проанализирован полный массив измерений глубоководных течений начиная с 1960 года. После оценки качества данных и приведения к горизонтам 500, 750 и 1000 м сформирована таблица, демонстрирующая обеспеченность, повторяемость направления и средние оценки скоростей течений. Анализ вертикальных профилей показал, что векторы скорости течений на некоторых станциях в приповерхностном и глубинных слоях имеют близкие направления. Однако на большинстве из рассмотренных профилей направления скорости на разных горизонтах существенно отличаются. Для каждой станции и каждого горизонта были построены и проанализированы диаграммы направлений и модуля скорости течений, они использованы для иллюстрации случаев разворота течений на разных горизонтах. Абсолютная величина вектора скорости на горизонтах глубже 500 м может превышать значение в вышележащих слоях.

The mechanism of generating barotropic long waves on the Black Sea Turkish coast is studied. Influence of the shelf shape and width upon the spatial-temporal parameters of the edge waves' lower modes is noted based on solution of the complete boundary-value problem using the developed algorithms of the finite-difference approximation. To simulate the generated on the Anatolian coast waves induced by the climatic wind, the three-dimensional model (for the Black and Azov seas) of the Institute of Numerical Mathematics of RAS is used. Position of the wave attenuation points and maximums of the level oscillations' amplitudes depending on the topography feature in the boundary area (the shelf and the continental slope zone) are studied. It is shown that the profile absolute maximum of the first mode wave is achieved at the coast and above the shelf edge. Increase of the continental slope width leads to slower decay of a wave towards the open sea. Convergence of the dispersion curves at high frequencies for various widths of the shelf is demonstrated. At the intermediate frequencies on the wide shelf, the dispersion curves are horizontal and their group velocity is close to zero. Having been studied, the spatial-temporal characteristics of the edge waves at real bottom profiles show that the waves with the longest periods arise in the region of the Ince Burnu that is due to manifestation of the zero mode of the trapped edge waves. The graphs of the dispersion curves and the maps of the amplitude functions of the shelf modes are constructed for the Anatolian coast. The model time series of the sea level are analyzed to calculate spectral density of the water level oscillations' power at the coast using the fast Fourier transformation. The spectra of the level oscillations' amplitudes for the shelf and deep sea stations of the Anatolian coast are represented.

Subinertial waves at the Black Sea shelf have been thoroughly studied in the last decades from the theoretical, observational and experimental points of view. Results of numerical prognostic experiments on modeling of the Black Sea circulation based on thermo-hydrodynamic eddy-resolving MHI model are studied. Spectral peaks in the oscillations of the current velocity component vector, temperature, salinity and vertical velocity are identified for the selected stations by means of the Fourier spectral analysis. The obtained energy-transporting oscillations are interpreted using expert estimates and comparison with the previous research. Time range of numerical calculation is conditioned by availability of data on the mass and energy external flows (reanalysis of the atmosphere state). Hydrodynamic parameters for April, 2006 and May - September, 2013 are considered. It is noted that seasonal variability of stratification and the model high sensitivity to the wind effects condition spectral characteristics of the wave processes on sub-inertial scales and intensity of mixing of the upper mixed layer. Two main energy-carrying intervals where the oscillations are confidently reconstructed by the modelare pointed out: large-scale relatively slow movements with the periods from 4 to 7 days and short-period waves with the periods from 10 to 40 hours. Due to relatively smooth bathymetry, origins of the short-period oscillations are hard to trace.